In the manufacture from a strip of stock material of parts such as electrical terminals, flat spring elements, and the like, it is often necessary that there be imparted to the strip an intermittent movement by which it is advanced step by step into a station at which one of such parts is punched out of or otherwise formed from the strip during the pause intervening each step movement. Various mechanisms for providing such stepwise movement to a strip have been heretofore proposed as follows.
U.S. Pat. No. 1,860,144 issued Mar. 24, 1932 to H. J. Gaisman et al. discloses a mechanism for advancing stepwise a strip having perforations thereon and from which razor blade blanks are formed. The mechanism comprises a reciprocably movable member disposed adjacent to the path of the strip, a finger pivotally mounted on the front end of such member to project toward and register with the perforations in the strip, and a spring urging the finger to contact the strip and enter the perforations. The mentioned member undergoes in alternation forward and reverse strokes parallel to the strip path. At the start of the forward stroke, the finger is seated in a strip perforation so as to cause such stroke to propel the strip one step forward against a frictional retarding force exerted on the strip by a brake. At the beginning of the return stroke, the finger is caused by the holding of the strip by such force to emerge from such perforation against the bias exerted on the finger by such spring, and to then slide over the strip during the return stroke until, at the end of it, the finger becomes seated in the next perforation.
U.S. Pat. No. 2,768,826 issued Oct. 30, 1956 to H. D. Gaite discloses a mechanism for advancing, say, perforated telegraph tape, stepwise, the device comprises a drive member disposed below the tape path and having at its tip a series of pins adapted to be entered into and retracted from pilot perforations in the tape. A reversibly movable link is connected to such member to exert thereon a force inclined to the vertical so as to exert on the member a vertical force component which is alternately up and down and a horizontal force component which is alternately forward and reverse. Various stop elements cooperate with the drive member to constrain its movement in response to such inclined force to an up-forward-down-reverse rectangular movement transmitted to the pins to cause them to move the tape stepwise by, in sequence, entering the pilot perforations of the tape, advancing it a step, retracting from the perforations, and returning to start position.
U.S. Pat. No. 1,403,106 issued Jan. 10, 1922 to R. W. Pittman discloses a mechanism for advancing motion picture film stepwise. The mechanism comprises a carrier operable by a crank to longitudinally reciprocate forward and back parallel to the path of the film, a pair of arms slidably mounted by the carrier to be transversely movable towards and away from the film, and means operated by the crank to give the arms a transverse reciprocating motion causing them to enter into and retract from the feed perforations in the film. That transverse motion is coordinated with the longitudinal reciprocating movement of the the carrier such that the pins undergo in relation to the film an in-forward-out-reverse movement producing stepwise advancement of the film.